# How does this capacitor discharge?

I have this schematics here

Does anyone know how the capacitor in the black circle (disregard the blue circles) can discharge once it is charged up and the power has been disconnected.

It is suggested that it is discharged through the resistor but this cant be because once it is charged its left plate will be +5Vcc and the right plate 0V so to discharge through the resistor the charge would have to go through the insulation through the resistor and to ground?? Witch is impossible unless the capacitor is bad.

• There is NO ideal capacitor. The real equivalent is with a resistor (high value) in parallel with capacitance, which is the insulator between plates resistance. So there is leakage current all the time. Typically in in electrolytic capcitors the leakage current is around 5~15μA per μF, which is really high! Feb 2, 2015 at 8:51
• Thinking and questioning are both extremely good ideas - they will take you far. BUT do also listen to what people say and work through stuff you do not understand. If in doubt ask. Ambiorix's "-5V" explanation is essentially correct but you tend to reject it as unlikely, without having any reason to do so than intuition. In this case intuition fails. The voltage across a capacitor cannot change instantaneously nor if no current flows. At power-off there is +5V across the cap. When V+ falls to 0V there is still 5V across the cap so the bottom must be at -5V. In practice things like IC body ... Feb 2, 2015 at 9:34
• ... diodes and other muddy the waters but that shos the basic principle. Feb 2, 2015 at 9:35
• i did not reject -5v explanation, look below :) Feb 2, 2015 at 10:36